<!DOCTYPE html>
<link rel="stylesheet" href="test-common.css">
<style type="text/css">
  @counter-style a {
    system: extends decimal;
    negative: '!';
    negative: 0;
    negative: ~;
    negative: '(' 'x' ')';
  }
</style>
<ol start="-2" style="list-style-type: a">
  <li><li><li><li><li>
</ol>
